comparison of aspirin renogram and captopril renogram in the diagnosis of renovascular hypertension

renal artery stenosis (ras) is the most common cause of secondary hypertension. preliminary data indicate that aspirin renography with hippurate may be more sensitive for detection ras. in this study 20 patients with known or suspected ras underwent aspirin renography (20 mg/kg orally 1 hour before injection of radiotracer) and captopril renography (50 mg orally) with 99mtc-dtpa. renal angiography was performed in all patients. of the 20 patients enrolled, 11 had unilateral ras on angiography. captopril renography was positive in 10 patients (91% sensitivity and 90% specificity). aspirin renogram showed 9 patients with ras correctly (81.8% sensitivity and 100% specificity). our data suggest that aspirin renography with 99mtc-dtpa has comparable sensitivity with captopril in detection of unilateral ras.